Son accused armed robbery he is innocent and cops want him to take lie detector, they have been harassing him search warrant

You should hire an attorney immediately.

Can I apply for a US Visitor Visa (B1/2) with an approved I-140? Having been employed outside of US (in UK) for 2.5 years.

Theoretically possible if you can prove you have no immigration intent.

F-1 Transfer Pending but new school season started. Can I attend?

Your current school and transfer school need to have your transfer updated in SEVIS with a new I-20 issued.

Will the one year filing deadline for Asylum affect me if I just changed my religion - from Iran?

Yes, it will effect you, but you are not barred for applying for asylum due to "changed circumstances".

I was given a pre interview case review about 2 weeks ago for the N400 . How many days does it take to get an interview date?

It really depends. May take a few months.

This is a common scenario. Unless he can prove fraud, you should be fine.

Hard to tell. There is always the chance they can take him back into custody.

Yes if you intend to marry within 90 days.

Change of visa from F2 to H4. I have got approved my H1 visa and it will start from Oct 1st 2014.

Make sure she applies for change of status while she is in lawful status.

Do I have to impute interest on a loan I made to a foreign corporation if my tax home is a foreign country with a treaty?

Speak to you accountant or a tax lawyer.